Newport Castle was built in the 14th century, probably by Hugh de Audley, 1st Earl of Gloucester or his son-in-law, Ralph, Earl of Stafford, with the purpose of managing the crossing of the River Usk. The castle was used as administrative offices for the collection of rent and dues from local tenants, and was also a residence and a garrison. In 1402 it was sacked by Owain Glyndŵr. It was in disrepair by 1522, and was taken by Oliver Cromwell's forces during the Civil War. Its use declined further in later centuries.
The castle was built of Old Red Sandstone and local grey limestone. Originally, it was surrounded by a moat, within a rectangular walled court. It had three tall towers, a large rectangular central tower and two two-storey polygonal end towers, which connected by straight walls.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.